Duplicate Billing

Hi, I had a DSTV price lock that expired in December 2016 and in January 2017 I renewed my price lock for 24 months, it appears that the one was never cancelled and i have been billed twice for the last year. I queried this in June and was advised that the error has been corrected, I requested a statement as at 18 June 2016 and the balance was R2 989.43 which I still belive was incorrect, but decided to pay it in order to put the matter to rest, my accounts has now been blocked and DSTV is claiming that I owe them in access of R7 000.00. I have spend more than 4 hours on the phone with 7 different consultants, I have even emailed my bank statement proving that the debit orders have been deducted, but I keep on being told that the DPP department will get back to me... 2 weeks later nobody has gotten back to me... I have exhausted all avenues and simply dont know what to do anymore as I have been paying every month, but my subscription has been suspended and I have a R7 000.00 hanging over my head (in error). Kind Regards Eon